Linear Actuator Brake Coupling for Fast Controlled Back-Rest Lowering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing linear actuators in hospital beds are unable to rapidly lower the back-rest section to a horizontal position without causing harmful collisions due to insufficient speed, leading to potential trauma for patients and structural overload, and previous solutions such as gas springs complicate the structure and increase costs.
Innovation Solution
A linear actuator with a coupling between the brake means and spindle nut, where the brake means engages or disengages at a predetermined position, allowing for controlled speed reduction and maintaining a dampening effect, thereby reducing lowering time and preventing collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the spindle is made non-self-locking to enable quick release for rapid lowering, then the lowering speed is improved, but the back-rest section rushes downwards with uncontrolled acceleration causing collision-like braking
Solution Approach 1:
A brake means is introduced as an intermediary element between the load and the spindle. The brake means includes a brake element that can be selectively engaged with a brake contact surface on the spindle to provide controlled friction braking during the lowering process, preventing uncontrolled acceleration while maintaining the ability for rapid positioning when disengaged
2Object-affected harmful factors
If gas springs are added to dampen the movement and prevent collision, then the harmful braking effect is reduced, but the structure becomes more complex and expensive
Solution Approach 1:
The brake means is merged with the existing spindle assembly by integrating the brake element and brake contact surface directly into the quick release mechanism. This allows the braking function to be combined with the positioning function, eliminating the need for separate gas spring components and their associated mounting brackets
Solution Approach 2:
The brake means is designed to be self-contained within the actuator assembly, using the spindle's own structure (brake contact surface) as part of the braking mechanism. The brake element can be spring-loaded or manually actuated to engage with the brake contact surface, providing self-sufficient damping without external gas springs
3Object-affected harmful factors
If brake means are permanently engaged on the spindle, then the lowering speed is controlled, but the lowering time increases and productivity decreases
Solution Approach 1:
The brake means is designed with selective engagement capability, allowing the brake element to be engaged or disengaged from the brake contact surface based on operational requirements. This dynamic control enables the system to switch between controlled lowering (brake engaged) and rapid positioning (brake disengaged) modes, optimizing both safety and productivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a controlled and rapid lowering of the back-rest section, reducing the risk of trauma and structural overload while maintaining a cost-effective and simplified bed structure by engaging the brake means only when necessary, thus enhancing safety and reducing the complexity and cost associated with gas springs.
Implementation Method 1
a brake means (52) and a corresponding position means (58) and coupling (91)... the brake means engages or disengages at a predetermined position, allowing for controlled speed reduction and maintaining a dampening effect
Data Source
Figure 1~3
Figure 4
Figure 5
AI summary
Linear actuator comprising a reversible electric motor (20), a transmission (21), a non- self-locking spindle (22), where the reversible electric motor (20) through the transmission (21) drives the non-self-locking spindle (22) and a spindle nut (23) on the spindle (22). The actuator further comprises an adjustment element (24) secured against rotation and where the adjustment element (24) can be moved axially, as it is connected to or integrated with the spindle nut (23) on the spindle (22). Further, that actuator comprises position means for determining the position of the spindle nut (23), brake means for controlling the speed of the spindle nut (23) under the external load. Between the brake means and the spindle there is a coupling in connection with the position means for determining the position of the spindle nut (23). The coupling engages the brake means to the spindle or disengages the brake means from the spindle, when the spindle nut (23) is in a predetermined position on the spindle (22).